Am I getting scammed

So I’ve been on gameflip for a while, mostly to sell steam wallet codes so that I would be able to add the proceeds from the purchases to my paypal balance. So far I’ve sold a couple cards with no issue, but today somebody made a dispute saying that when they tried to use the code, it was already used. I took a look and noticed that the person making the dispute was relatively new to gameflip, with their account being created this March. Nobody else I sold to had issues with their purchases and the deals went through smoothly, except for this one case. Is this a scam and have there been any other scam attempts similar what’s happening right now?
Invite Code: 9SQKYC

Hello! I just checkd your sale and saw that we sent the buyer a ticket asking for more information about this issue. Please send me a PM with the activation time for this code in particular (in order to get that, please contact Steam support). I’ll be able to help you further.


Hello, thanks for responding. Just a quick question, how do I get the activation time? I’m not sure how to contact steam support about it.

Please check this link for further help about your question:

This is what shows up when I try to ask steam support about anything. The first choice would indicate that my steam code was damaged, but that’s not necessarily the case since I just want to find the activation time. Do I still use that link and ask for the activation time instead?
This is the link I’m talking about

I think you can contact them that way, but I can’t confirm. Please try and let me know. Also let’s continue this conversation via PM.